The present invention relates to a low depth, nestable tray for transporting and storing containers, more particularly, the present invention relates trays that combine low depth with high stability for PET plastic bottles having a one liter capacity.
Bottles, particularly for soft drinks and other beverages, are often stored and transported during the distribution stages thereof in crates or trays. The term "crate" or "tray" as used herein includes crates, trays and similar containers having a bottom and peripheral sidewalls. These crates generally are configured to be stacked on top of each other when loaded with bottles. The crates also are configured to be nested together when empty of bottles. The plastic crates provide advantages such as conservation of storage space and efficient, easy handling and recyclability. In order to minimize the storage space of the crates when nested and to reduce cost and weight, many crates today are made with a shallow peripheral wall. These generally are referred to as "low depth" crates. Crates having a higher peripheral wall generally are referred to as "full depth" crates.
The sidewalls and internal supports and dividers of a full depth crate extend higher on the bottles within the crate and thus generally provide improved support for the bottle. However, the nested heights of empty, stacked full depth crates is greater than that of low depth crates. Low depth crates also are generally less expensive and lighter in weight than similarly constructed full depth crates. Thus, low depth crates are used extensively.
Low depth bottle crates for PET plastic bottles of one, two or three liter capacity have generally been designed for bottles having a straight-cylindrical body with tapering tops. An example of a known bottle crate is disclosed in commonly assigned U.S. Pat. No. 4,978,002 to Apps, et al, the disclosure of which is hereby incorporated by reference in its entirety.
Containers placed in low depth cases extend above the side walls. Thus, containers in a lower case must be able to support the weight of the other cases stacked on top of them.
Plastic bottles are widely used as containers for retailing soft drinks and other beverages. One type of plastic, polyethylene terephthalate (PET), has become particularly popular because of its transparency, light weight, and low cost. In addition to being flexible, the walls of PET bottles are strong in tension and thus can safely contain the pressure of a carbonated beverage. Moreover, conventional PET bottles can bear surprisingly high compressive loads, provided that the load is directed substantially along an axis symmetric or in line with the longitudinal axis of the bottle. A single PET bottle can support the weight of many bottles of the same size filled with fluid if the bottle is standing upright on a flat, horizontal surface and the weight of the other bottles is applied to the closure of the single bottle and is directed substantially vertically along the symmetric axis. However, if a compressive load is applied to a conventional PET beverage bottle along a direction other than the longitudinal axis of the bottle, the bottle tends to buckle. Thus, a crate intended to be stacked must ensure that the compressive load is directed substantially vertically along the longitudinal axes of the bottles.
PET bottles are ordinarily packed by bottlers in cases or other containers, several bottles to the case, for shipment to retailers or for storage. Cases of bottles are customarily stacked on top of each other. One way of handling the cases of bottles is to stacked the cases on pallets which can be lifted and moved about by fork-lift trucks. A technique for interconnecting columns of cases, is called cross-stacking, and is often used to improve stability of a stack of cases, or for display purposes by the retailer. There has been a need for bottle cases having structural features which facilitate stacking and cross-stacking of loaded cases, and enhance stability of columns of such cases.
One of the problems experienced with previous nestable trays is the absence of structural features which ensure that the loaded bottles will be maintained in a substantially vertically upright position to most advantageously bear the compressive load of bottles stacked thereabove while avoiding the possibility of buckling or other failures due to non-axial compressive loads. The present invention provides structural features to ensure that the bottles are maintained in a vertically upright position with minimal movement and jostling during handling of stacked and cross-stacked trays.
Other problems experienced with previous nestable trays include spreading or fraying of the side walls and "shingling" between trays placed in close side-by-side or end-to-end relation. The spreading or fraying problem often compounds the "shingling" problem. The present invention addresses both of these frequent complaints of previous trays. Structural supports to prevent spreading or fraying of the side walls are provided, which in turn help alleviate the "shingling" problem. Moreover, the side walls of the present tray are provided with additional structural improvements to avoid "shingling."
As to "shingling," previous nestable trays, which have nesting tabs or ribs on the exterior of the side walls, often are not easily handled because the tabs or ribs on the exterior of the side walls provide a catch surface between trays which come into contact. When stacks of trays are placed in close side-by-side and end-to-end relation, any catch surface such as a rib or tab on the exterior of the band will tend to land and rest on the upper edge or rim of the band of a neighboring tray. This overlapping of adjacent trays causes one end of the tray to be raised with respect to the other and is commonly referred to as "shingling". Shingling is disruptive of load stability on a pallet since it initially prevents the achievement of a perfectly squared load. Stacks which are unstable because of shingling are undesirable and can be a hazard. There exists a need for a nestable tray which is constructed to avoid shingling.
Spreading or fraying of side wall structures from nesting is a problem encountered with previous nestable trays. When a large number of trays are nested, the side walls of the trays near the bottom of the nested stack, which bear more of the load, have a tendency to spread or splay outward because no structural provision has been made for supporting the weight of trays nested above. This damage has a cumulative effect and results in a shorter service life for the trays, and thus additional expense for replacement. The shingling problem can be compounded in trays having no provision to prevent spreading or fraying. Any nesting tabs or ribs on the exterior of the side walls are even more prone to shingling or catching on other trays as the side walls spread outward. There has been a need for trays which maintain their structural integrity over repeated uses in both nested and loaded configurations. The present invention addresses the spreading problem by providing structural features to support the weight of stacked and nested trays. Since shingling is often compounded by spreading, this improvement alone would greatly alleviate the shingling problem. Moreover, as discussed above, the present tray also provides structural features on the outside of the side walls to prevent shingling.